Portable, battery operated electrical devices are in widespread use. Typically, such devices include flashlights, lanterns, and small electric motors such as used for electric razors and small personal fans. These devices generally are powered by one or the other of two types of dry-cell batteries, namely, disposable batteries or rechargeable batteries. The life of such batteries is relatively limited before they must be replaced or recharged. In addition, dry cell batteries are relatively heavy for their size, and they present an environmental hazard when they are discarded.
Solar cell devices exist for converting sunlight or other light energy into electricity for powering a variety of different devices. Hand-held solar cell generator devices are used, for example, for powering small pocket-sized electronic calculators and other similar devices. The problem with solar cell devices, however, is that they require sunlight or other relatively strong light to function. Such devices, consequently, are not of value at night, or in darkened rooms.
Devices have been developed for thermo-electrically generating power to operate wristwatches. The heat for operating the thermoelectric generator for such watches is obtained from the wrist of the wearer. Four patents disclosing devices of this type are the patents to Pack U.S. Pat. No. 3,018,430; Compte U.S. Pat. No. 4,165,477; Dolezal U.S. Pat. No. 4,212,292; and Baumgartner U.S. Pat. No. 4,320,477. Sufficient power is generated by the thermo-electric generators of these watches to continuously operate the watches, so long as they are worn on the wrist. Consequently, it is not necessary to replace batteries in these devices.
Small non-battery portable electric generators for personal use, employing other techniques have been developed. For example, the device shown in the patent to Horrell U.S. Pat. No. 2,463,538 is a small hand-held electromagnetic generator in which a wheel is rotated by means of air pressure generated from a flexible rubber squeeze bulb. The limitations of this device are readily apparent, since the bulb must be squeezed continuously to produce the air supply for driving the generator.
A different approach to an electrical generator of a non-conventional type also is disclosed in the patent to Hayes U.S. Pat. No. 4,409,489. This patent discloses a network of collapsible tubes placed over a roadway or other area traversed by motor vehicles. Working fluid is placed in the tubes, which are attached to a turbine generating system. Vehicles moving over the tubes cause the generation of electricity. Obviously, when the vehicles are not present, the electricity generation terminates.
Another small, air-driven turbine generator is disclosed in the patent to May U.S. Pat. No. 4,511,806. This turbine is placed in the fluid line for an underwater breathing system, to be driven by the fluid coming from the oxygen tanks before it is delivered to the breathing apparatus of the diver. Consequently, electricity for use by the diver is provided, so long as air is supplied from the oxygen tanks. Salt water activated generators, employing metallic anodes and compatible cathodes also have been developed. Typically, a salt water or brine solution is placed in a tank which also contains an anode and a cathode, connected to the electrical load to be energized. So long as the salt water solution is maintained and until the anode is consumed, these devices produce usable amounts of electricity. Typically, however, devices of this type are not small, hand-held devices, and they have limited life, determined by the rate of depletion of the anode and/or cathode materials used in them.
Accordingly, it is an object of this invention to provide an improved small, portable electrical generator which is inexpensive, uses no volatile fuels, is operated from readily available materials, and which utilizes replaceable components for extended life of the device.